However, MEPs did not demand Selmayr's removal, nor an immediate reopening of the appointment procedure.

Instead, they asked the commission to "reassess" the procedure "in order to give other civil servants the possibility to apply."

They admitted that "the revocation of a favourable administrative act is generally not possible due to legal constraints."

But they called on the commission to present new rules for the appointment of senior officials before the end of the year.

"The commission must now take the next steps and should conduct open and transparent application procedures in the future", said Inge Graessle, the centre right MEP who chairs the budgetary control committee where the resolution was drafted.

The commission reacted within minutes of the vote, insisting that Selmayr "cannot be revoked".

Guenther Oettinger, the commissioner in charge of human resources, said in a statement that the EU executive was "ready" to reassess procedures, but through an "inter-institutional round table" that would not limit the change to its own staff.

"Senior management appointments should under no circumstances become the subject of negotiations between member states and political parties," Oettinger added, in an not-so-implicit rejection of MEPs' demands.

"The debate is over," Manfred Weber, the leader of the EPP group in the parliament, and a political ally of Oettinger and commission president Jean-Claude Juncker, told EUobserver after the vote.

But in sign of MEPs from all groups' unease, Weber declined to comment further.

Juncker's 'blackmail'

"There were splits within all groups", a parliament source noted.

Some in the Green, far-left GUE/NGL, liberal Alde or centre-left S&D groups called for Selmayr's resignation, while in the EPP, many were shocked by the way Selmayr was appointed.

But in the end, the parliament's two main groups, the EPP and the S&D, settled for a compromise that expressed the assembly's anger while sparing Selmayr and the commission's president Jean-Claude Juncker.

Juncker had threaten to step down if Selmayr, who was Juncker's powerful head of cabinet until his promotion, was forced to resign.

"We have to support the commission, in a very specific context," EPP French MEP Francoise Grossetete argued on Wednesday, referring to the Brexit negotiations and the upcoming European elections.

Last month, Grossetete had compared Selmayr surprise appointment to a "mystery worthy of the Chinese Communist Party".

"In Europe, it's a failure to be too ideological," one of the groups' grandees said. "You have to be pragmatic."

But "Juncker angered a lot of people, including within the EPP," a parliament source told this website.

"It was a blackmail, it was not very elegant," said an MEP.

According to different sources, some commissioners even called MEPs to warn them that Juncker's threat was to be taken seriously, and some amendments to the resolution were 'copy-pastes' of answers sent by the commission to the budgetary control committee's questions.

'We all pretend'

In the end, MEPs chose to use the word "reassess" the appointment procedure, rather than the word "reopen", so the commission is not obliged to reconsider Selmayr's appointment.

"We all pretend that we adopted something big, but we just gave up our democratic power," another MEP told EUobserver, regretting a "fatigue" among her colleagues.

She noted however that the commission had lost a lot of credit in the EU assembly.

"Everyone thinks now that the commission is already finished, and that it will be even more the case after the summer break," one source noted.

A third MEP argued that the EU executive would still be able to get legislative work through until the end of its mandate in 2019, but only because "Juncker has a performing team of commissioners around him".